Saturday 5 May 2012 19.05 EDT
First published on Saturday 5 May 2012 19.05 EDT

W H Auden once asked playfully: "When life fails/ What's the good of going to Wales?" Mark Haddon's The Red House could have been written to answer the question. This hugely enjoyable, sympathetic novel would make perfect reading for those setting out on holiday in Britain – and especially anyone heading for Wales. The most ambitious thing about it is its lack of ambition, its cool decision not to include any dramatic events beyond a twisted ankle on a Welsh hillside, a brush with hypothermia and a controversial kiss between teenage girls. Its agenda is other – it looks at the inner workings of people on holiday and at ordinary unhappiness in many forms – a family variety pack.

The cast is extended: Richard, a hospital consultant, comes with smart, attractive, working-class wife, Louisa, and stepdaughter, Melissa, who in spite of a "glossy thoroughbred look and "slow-motion hair", proves – as more than one person will discover – surly and unrewarding to kiss. Richard has invited along his less successful sister, Angela, and her family, as a kindly gesture in the wake of their mother's death. Angela's husband, Dominic, is unfulfilled and unfaithful. They have three children: athletic Alex, god-fearing Daisy and eight-year-old oddball Benjy.

"Behind everything there is always a house," Haddon asserts – which may be straining a point. But he uses the house stylishly to give his novel form, and its walls, and the architecture of a single week, contain the characters at their most chaotic. He registers the way each individual lives, helplessly, under a separate emotional roof. He shows that being in a family is a faltering experiment. And at one point he notes "how eloquently houses speak, of landscape and weather".

Yet the striking thing about Haddon's The Red House is that it is withheld and somehow circumspect. It is a book of minor revelations and slow-release secrets. When Daisy makes her peace with discovering she is gay, she experiences a surge of power – a delicately described moment of self-acceptance. Haddon writes beautifully about Daisy. He turns out to be better on teenagers than on the middle-aged. Perhaps he has more sympathy with them. By far his weakest character is Daisy's abject mother, Angela, who cannot let go of grievances about her brother. The grievances themselves are convincing but Angela's haunted obsession with a stillborn daughter, Karen – whom she lost 18 years earlier – is implausible. Karen keeps irritatingly gatecrashing what is, in her absence, a more subtle story.

Speaking of irritation, Haddon is especially good at the inevitability of it within families. Melissa finds her stepfather's habit of doing the crossword in pencil maddening (one sympathises). Angela cannot stick the way her sister-in-law holds a measuring jug up to the light "as if it were a syringe and life hung in the balance". And Dominic finds Richard's luxuriant crest of black hair an affront.

Haddon has a restless sense of the absurd and a genius for shorthand, for packing paragraphs full (take the ground-gobbling opening paragraph about the train journey to Wales). He catches the entire texture of the holiday complete with extracts from books read and words from music listened to – he is a great man for lists. The writing is, at every turn, a tremendous pleasure. And while the novel cannot compete with Haddon's one-off bestseller The Curious Incident of the Dog in the Night-Time, it is still a treat to be part of this Welsh escapade.

At the end, Benjy records in the visitors' book: "I liked walking up the hill and the rain strom and sheepherds' pie at the grannery." It is a delicious moment because we know that the visitors' book cannot begin to describe the holiday as it has actually happened. We have been absorbed, entertained and moved by the entry that will never appear: the novel itself.